/* #pragma ident        "@(#)g_imp_name.c       1.26    04/02/23 SMI" */

/*
 * Copyright 1996 by Sun Microsystems, Inc.
 *
 * Permission to use, copy, modify, distribute, and sell this software
 * and its documentation for any purpose is hereby granted without fee,
 * provided that the above copyright notice appears in all copies and
 * that both that copyright notice and this permission notice appear in
 * supporting documentation, and that the name of Sun Microsystems not be used
 * in advertising or publicity pertaining to distribution of the software
 * without specific, written prior permission. Sun Microsystems makes no
 * representations about the suitability of this software for any
 * purpose.  It is provided "as is" without express or implied warranty.
 *
 * SUN MICROSYSTEMS DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
 * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
 * EVENT SHALL SUN MICROSYSTEMS BE LIABLE FOR ANY SPECIAL, INDIRECT OR
 * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF
 * USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
 * OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
 * PERFORMANCE OF THIS SOFTWARE.
 */

/*
 *  glue routine gss_import_name
 *
 */

#include "mglueP.h"
#include "k5-der.h"
#include <stdio.h>
#ifdef HAVE_STDLIB_H
#include <stdlib.h>
#endif
#include <string.h>
#include <errno.h>

/* local function to import GSS_C_EXPORT_NAME names */
static OM_uint32 importExportName(OM_uint32 *, gss_union_name_t, gss_OID);

static OM_uint32
val_imp_name_args(
    OM_uint32 *minor_status,
    gss_buffer_t input_name_buffer,
    gss_OID input_name_type,
    gss_name_t *output_name)
{

    /* Initialize outputs. */

    if (minor_status != NULL)
        *minor_status = 0;

    if (output_name != NULL)
        *output_name = GSS_C_NO_NAME;

    /* Validate arguments. */

    if (minor_status == NULL)
        return (GSS_S_CALL_INACCESSIBLE_WRITE);

    if (output_name == NULL)
        return (GSS_S_CALL_INACCESSIBLE_WRITE);

    if (input_name_buffer == GSS_C_NO_BUFFER)
        return (GSS_S_CALL_INACCESSIBLE_READ | GSS_S_BAD_NAME);

    if (input_name_type == GSS_C_NO_OID ||
        !g_OID_equal(input_name_type, GSS_C_NT_ANONYMOUS)) {
        if (input_name_buffer->length == 0)
            return (GSS_S_BAD_NAME);

        if (input_name_buffer->value == NULL)
            return (GSS_S_CALL_INACCESSIBLE_READ | GSS_S_BAD_NAME);
    }

    return (GSS_S_COMPLETE);
}

static gss_buffer_desc emptyNameBuffer;

OM_uint32 KRB5_CALLCONV
gss_import_name(OM_uint32 * minor_status, gss_buffer_t input_name_buffer,
                gss_OID input_name_type, gss_name_t * output_name)
{
    gss_union_name_t    union_name;
    OM_uint32           tmp, major_status = GSS_S_FAILURE;

    if (input_name_buffer == GSS_C_NO_BUFFER)
        input_name_buffer = &emptyNameBuffer;

    major_status = val_imp_name_args(minor_status,
                                     input_name_buffer, input_name_type,
                                     output_name);
    if (major_status != GSS_S_COMPLETE)
        return (major_status);

    /*
     * First create the union name struct that will hold the external
     * name and the name type.
     */
    union_name = (gss_union_name_t) malloc (sizeof(gss_union_name_desc));
    if (!union_name)
        return (GSS_S_FAILURE);

    union_name->loopback = 0;
    union_name->mech_type = 0;
    union_name->mech_name = 0;
    union_name->name_type = 0;
    union_name->external_name = 0;

    /*
     * All we do here is record the external name and name_type.
     * When the name is actually used, the underlying gss_import_name()
     * is called for the appropriate mechanism.  The exception to this
     * rule is when the name of GSS_C_NT_EXPORT_NAME type.  If that is
     * the case, then we make it MN in this call.
     */
    major_status = gssint_create_copy_buffer(input_name_buffer,
                                            &union_name->external_name, 0);
    if (major_status != GSS_S_COMPLETE) {
        free(union_name);
        return (major_status);
    }

    if (input_name_type != GSS_C_NULL_OID) {
        major_status = generic_gss_copy_oid(minor_status,
                                            input_name_type,
                                            &union_name->name_type);
        if (major_status != GSS_S_COMPLETE) {
            map_errcode(minor_status);
            goto allocation_failure;
        }
    }

    /*
     * In MIT Distribution the mechanism is determined from the nametype;
     * This is not a good idea - first mechanism that supports a given
     * name type is picked up; later on the caller can request a
     * different mechanism. So we don't determine the mechanism here. Now
     * the user level and kernel level import_name routine looks similar
     * except the kernel routine makes a copy of the nametype structure. We
     * do however make this an MN for names of GSS_C_NT_EXPORT_NAME type.
     */
    if (input_name_type != GSS_C_NULL_OID &&
        (g_OID_equal(input_name_type, GSS_C_NT_EXPORT_NAME) ||
         g_OID_equal(input_name_type, GSS_C_NT_COMPOSITE_EXPORT))) {
        major_status = importExportName(minor_status, union_name, input_name_type);
        if (major_status != GSS_S_COMPLETE)
            goto allocation_failure;
    }

    union_name->loopback = union_name;
    *output_name = (gss_name_t)union_name;
    return (GSS_S_COMPLETE);

allocation_failure:
    if (union_name) {
        if (union_name->external_name) {
            if (union_name->external_name->value)
                free(union_name->external_name->value);
            free(union_name->external_name);
        }
        if (union_name->name_type)
            generic_gss_release_oid(&tmp, &union_name->name_type);
        if (union_name->mech_name)
            gssint_release_internal_name(minor_status, union_name->mech_type,
                                        &union_name->mech_name);
        if (union_name->mech_type)
            generic_gss_release_oid(&tmp, &union_name->mech_type);
        free(union_name);
    }
    return (major_status);
}

static OM_uint32
importExportName(OM_uint32 *minor, gss_union_name_t unionName,
                 gss_OID inputNameType)
{
    gss_OID_desc mechOid;
    gss_buffer_desc expName;
    gss_mechanism mech;
    OM_uint32 major, mechOidLen, nameLen;
    uint8_t b2;
    const uint8_t *name;
    struct k5input in, oid, old_format;

    expName.value = unionName->external_name->value;
    expName.length = unionName->external_name->length;
    k5_input_init(&in, expName.value, expName.length);

    if (k5_input_get_byte(&in) != 0x04)
        return (GSS_S_DEFECTIVE_TOKEN);
    b2 = k5_input_get_byte(&in);
    if (b2 != 0x01 && b2 != 0x02) /* allow composite names */
        return (GSS_S_DEFECTIVE_TOKEN);

    mechOidLen = k5_input_get_uint16_be(&in);

    if (!k5_der_get_value(&in, 0x06, &oid))
        return (GSS_S_DEFECTIVE_TOKEN);
    /* Verify that mechOidLen is consistent with the DER OID length. */
    if (mechOidLen != k5_der_value_len(oid.len))
        return (GSS_S_DEFECTIVE_TOKEN);
    mechOid.length = oid.len;
    mechOid.elements = (uint8_t *)oid.ptr;
    if ((mech = gssint_get_mechanism(&mechOid)) == NULL)
        return (GSS_S_BAD_MECH);

    if (mech->gssspi_import_name_by_mech == NULL &&
        mech->gss_import_name == NULL)
        return (GSS_S_UNAVAILABLE);

    /*
     * we must now determine if we should unwrap the name ourselves
     * or make the mechanism do it - we should only unwrap it
     * if we create it; so if mech->gss_export_name == NULL, we must
     * have created it.
     */
    if (mech->gss_export_name) {
        if (mech->gssspi_import_name_by_mech) {
            major = mech->gssspi_import_name_by_mech(minor, &mechOid, &expName,
                                                     inputNameType,
                                                     &unionName->mech_name);
        } else {
            major = mech->gss_import_name(minor, &expName, inputNameType,
                                          &unionName->mech_name);
        }
        if (major != GSS_S_COMPLETE)
            map_error(minor, mech);
        else {
            major = generic_gss_copy_oid(minor, &mechOid,
                                         &unionName->mech_type);
            if (major != GSS_S_COMPLETE)
                map_errcode(minor);
        }
        return (major);
    }
    /*
     * we must have exported the name - so we now need to reconstruct it
     * and call the mechanism to create it
     *
     * WARNING: Older versions of gssint_export_internal_name() did
     *          not export names correctly, but now it does.  In
     *          order to stay compatible with existing exported
     *          names we must support names exported the broken
     *          way.
     *
     * Specifically, gssint_export_internal_name() used to include
     * the name type OID in the encoding of the exported MN.
     * Additionally, the Kerberos V mech used to make display names
     * that included a null terminator which was counted in the
     * display name gss_buffer_desc.
     */

    /* next 4 bytes in the name are the name length */
    nameLen = k5_input_get_uint32_be(&in);
    name = k5_input_get_bytes(&in, nameLen);
    if (name == NULL)
        return (GSS_S_DEFECTIVE_TOKEN);

    /*
     * We detect broken exported names here: they always start with
     * a two-octet network-byte order OID length, which is always
     * less than 256 bytes, so the first octet of the length is
     * always '\0', which is not allowed in GSS-API display names
     * (or never occurs in them anyways).  Of course, the OID
     * shouldn't be there, but it is.  After the OID (sans DER tag
     * and length) there's the name itself, though null-terminated;
     * this null terminator should also not be there, but it is.
     */
    if (nameLen > 0 && *name == '\0') {
        OM_uint32 nameTypeLen;

        /* Skip the name type. */
        k5_input_init(&old_format, name, nameLen);
        nameTypeLen = k5_input_get_uint16_be(&old_format);
        if (k5_input_get_bytes(&old_format, nameTypeLen) == NULL)
            return (GSS_S_DEFECTIVE_TOKEN);
        /* Remove a null terminator if one is present. */
        if (old_format.len > 0 && old_format.ptr[old_format.len - 1] == 0)
            old_format.len--;
        name = old_format.ptr;
        nameLen = old_format.len;
    }

    /*
     * Can a name be null?  Let the mech decide.
     *
     * NOTE: We use GSS_C_NULL_OID as the name type when importing
     *   the unwrapped name.  Presumably the exported name had,
     *   prior to being exported been obtained in such a way
     *   that it has been properly perpared ("canonicalized," in
     *   GSS-API terms) according to some name type; we cannot
     *   tell what that name type was now, but the name should
     *   need no further preparation other than the lowest
     *   common denominator afforded by the mech to names
     *   imported with GSS_C_NULL_OID.  For the Kerberos V mech
     *   this means doing less busywork too (particularly once
     *   IDN is thrown in with Kerberos V extensions).
     */
    expName.length = nameLen;
    expName.value = nameLen ? (uint8_t *)name : NULL;
    if (mech->gssspi_import_name_by_mech) {
        major = mech->gssspi_import_name_by_mech(minor, &mechOid, &expName,
                                                 GSS_C_NULL_OID,
                                                 &unionName->mech_name);
    } else {
        major = mech->gss_import_name(minor, &expName,
                                      GSS_C_NULL_OID, &unionName->mech_name);
    }
    if (major != GSS_S_COMPLETE) {
        map_error(minor, mech);
        return (major);
    }

    major = generic_gss_copy_oid(minor, &mechOid, &unionName->mech_type);
    if (major != GSS_S_COMPLETE) {
        map_errcode(minor);
    }
    return major;
} /* importExportName */